Adjustable switch for timers



Dec. 18, 1951 MORRISQN 2,578,824

ADJUSTABLE SWITCH FOR TIMERS Filed NOV. 50, 1950 2 $HEETSSl-1EET l .I/WE/yraz Dec. 18, 1951 D. MORRISON 2,578,824

ADJUSTABLE SWITCH FOR TIMERS Filed Nov. 30, 1950 2 SHEETS-SHEET 2 51 45 1?" if; 41 a; 40 34 59" 44 a? i I fr L un WI'IAIIII Patented Dec. 18, 1951 ADJUSTABLE SWITCH FOR TIMERS David Morrison, Manitowoc, Wis., assignor to Paragon Electric Company, Two Rivers, Wis., a corporation of Wisconsin Application November 30, 1950, Serial No. 198,265

9 Claims.

There is a type of defroster for refrigerators that comprises a switch driven by an ordinary clock so as to interrupt the energizing circuit of a, refrigerator at any selected time during each twenty-four hour period; the length of time that the circuit remains open being, however, fixed.

The rapidity with which frost forms varies Widely, depending not only on the type'of refrigerator but on the conditions of its use, so that the provision of a fixed defrosting period in most cases fails to achieve the best results.

It is my purpose to produce a switch device, for use in what may be termed the kitchen clock type of defroster, which may be set, by the mere shifting of a finger piece, to determine any desired length of defrosting period over a range so wide that an optimum setting may always be provided; and my further purpose that the switch openings and closings be rapid.

In carrying out my invention, I cause the clock to rotate a controlling cam once in twenty-four hours, as heretofore. However, the switch device is mounted so that it may be shifted through a limited distance; and the parts are 50 constructed that the cam allows the switch to remain open, during each revolution of the cam, for a period that increases progressively as the switch is shifted from one limit to the other.

Since the means for carrying out my invention may be used for other purposes than defrosting, an object of the present invention may be said to be the creation of a novel type of switch apparatus, wherein a switch is caused alternately to open and close rapidly by a rotatable cam i and wherein the relative lengths of the open and closed periods may be varied over a wide range through the mere shifting of a finger piece.

The various features of novelty whereby the present invention is characterized will hereinafter be pointed out with particularity in the claims, but, for a full understanding of the invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawings, wherein:

Figure 1 is a perspective view of a clock containing a switch apparatus embodying the present invention; Fig. 2 is a back view, on a larger scale, of the clock and switch, with the casing removed; Fig. 3 is a view similar to Fig. 2, showing only the switch means and controlling cam, with the switch about ready to open; Fig. 4 is a view similar to Fig. 2, the switch shown as having just opened; Fig. 5 is a front view of the controlling cam and the last gear wheel of the clock train, to which the cam is fixed; Fig. 6 is a side view of the switch means and the lever on which it is mounted, looking at the same from line 66 of Fig. 2; Fig. '7 is a section on line l'! of Fig. 2, the clock works being omitted; and Fig. 8 is a section, on a larger scale, on line 8-8 of Fig. 4.

Referring to the drawings, 10 is the casing of an electric clock provided with a depending stem H for setting the same. A gear wheel l2, added to the clock train, makes one revolution in twenty-four hours. One half of the front side or face of this gear wheel is black, as shown at M. The dial I5 of the clock contains a small hole I6 through which the front face of wheel [2 is visible. Whenever black shows through hole IE it is night time, the period in which defrosting is usually done.

The parts 0-1 6, just described, are in common use.

Coaxial and rotatable with gear wheel I2 is a cam IT, in the form of a disc of insulating mate rial having a cam edge i8. Said edge may conveniently be in the form of one turn of a spiral. with an abrupt drop from the high point I 9 to the low point 20.

On the main supporting plate 2| for the clock mechanism, beside gear wheel 12 and cam I1, is a long lever 22. The lever is hinged at one end to the plate so that, with the clock in an upright position, the lever extends down past the cam and out through the bottom of the clock casing where it terminates in a finger piece 22. The axis of the hinge pin 24 is parallel to the axis of the cam, so that. the lever may be swung toward and away from the cam.

In order that the lever shall remain in any angular position into which it is shifted, there is provided a brake device, best shown in Fig. 8. In the lever, a short distance from the hinged end, is a closed, transverse slot 22'. Extending through this slot is a post 25 fixed to plate 2!. Loose on this post is a washer 26 that rests on the lever. Surrounding the post and resting on this Washer is a coil spring 21. The spring is held under compression by a shoulder 28 on the upper end of the post. Thus the lever is at all times frictionally gripped and held between washer 26 and plate 2|. The length of the slot determines the angular distance through which the lever can swing.

On lever 22, opposite the cam, is a small slab 29 of insulating material, standing on edge and conveniently held in place by being secured to an arm 36 integral with and bent forwardly from the lever. Anchored at corresponding ends to member 29 are two cooperating spring switch blades, 3! and 32, that extend lengthwise of the lever and are normally out of engagement with each other, as in Fig. 4; so that the switch tends constantly to remain open. Blade 32 is longer than itsfree end and projects beyondthe free end of blade 3|. The extreme end of blade 32 is bent into a V the apex of which is on the side toward the cam. Also mounted on the lever, between the switch and the cam and extending lengthwise of the lever, is a switch actuator 34. The actuator is attached, at apointbetween its ends, to the lever by a pivot pin 3 5 so as to be rockable about the hinge axis of the lever. The

actuator terminates at one end in an arm 35,

having a part 35 in the plane-and bearing against the edge of the cam; the arm being tangential to the cam. A tension spring 31 is attached at o end to ti eectua cr nd t). 9 98 a n r strusk p i m thel rs i h spring being ,under an initial tension sufiicient to ho d ermfl fir ly. a ainst the Mounted on the actuator so as to movable, relatively to the latter, about the pivot pin this a flat shoe 39 o f insulating material. The shoe mayconveniently take the form of a sector of a disc. Inthe arrangement shown the sector has an angular width" of about ninety degrees and has-its arc-shaped edge formed in twosections of; different radii, scans,- with an abrupt shoulderfilz connectingthem. Rocking movements of shoe 39 are'lirnited by stops dd and ;45, respectively, on the actuator. The v parts are so proportioned that when the apex of the \[shaped end 32 ofswitch blade 32 rests-on the high-portion of the shoe, na mely that part '58 of the edge that is of the greater diameter bla'de -32 -is held firmly against the I, otherswitch blade; whereas, when element 32' registersfwith part il of the shoe edge, blade 32 stands free and out of contact with blade .3 I. -When-the def-roster is inuse cam..l1 turns through one revolution during each twenty-four hour day. :-No matter what the. setting oflever 22 is, arm 36 is at all times in contactwith the cam except, of course, during the instant while it is dropping abruptly from the high point to the low point,

Whenever the arm 35 dropsoifthe high end of the cam, spring ,3! drives. the arm quickly. against the low portion of the cam, theposition occupied in Fig. 2pand the switch closes quickly. The \I end :of blade 32- is at that time resting on be new section 49 of the edge of the. shoe, and the shoe bears against stop 44. As the cams turns in .the clockwise direction, the arm 36. is slowly pressed toward the ,left, tendingto' carry shoe 3!! along witnit, However, there. is friction between the shoe and switch blade 32. 50 that the shoe stands still,;allpwing stop. 44: to move awayfrom it until stop d5 engagesthe shoe and forces it to move with the; arm. Thereafter, the shoe .is carried along with; the ;actuator until,,as shown in Fig. 3, they endof blade 32 is about ready to drop off the trailing end, of edge section 40 of the shoe as in;Fig.- 3.; By the time that the cam turns through an additional, small angle, the switch;blade reaches the abrupt shoulder 42 and its V end acts asa wedge to throw the shoe ahead and once more in engagement with stop 34.; Thusthere is a snap action in the opening of theswitchp In Fig. 4; the parts are in thepositions wherein theswitch hasbeencpenedand the cam is well on the way to the position where the arm drop from the high point to the low point on the cam. As soon as the arm begins to drop off the high point of the cam, it starts driving the shoe in the clockwise direction; the abrupt shoulder 42 finally striking the near sloping side of the V end on switch blade 32 and quickly moving that blade into, engagement with blade. 3|; the parts assuming the positions which they occupy in Fig. 2. The switch is therefore closed in the same quick manner as is the opening thereof.

In the drawings the regulating lever is shown about midwa between its extreme positions. If it is shifted toward the right the switch will open-soonenbecause the swinging of the lever .toward the right in Fig. 2, for example, rocks tively turned in the clockwise direction; so that the r leasetaweeejth shoe tiles witch, exl ng in Fig. 3, cannot oc'c'iir untilthedistaiice etween the starter Contact of "Earth 36 with the can and the ropping-cabana on the can is mu ch less that it "'n'ow'is in Fig 3. "Adamant isp'os'sible if desired, so toproportion the parts that the arm drops off the high point Of tlie cam atthe instant that the V "endio'n switch blade 32' reaches the end ofthe siectionfoftl'ie shoe that holds the switch closed; 'i n iwhich case there will be no efiectivetopenin'g of'the'switch.

7 At any rate, it ispossible to'control the' time during which the switch remains open, by the mere shifting of a finge'npiecabetweeri aml'nimum and .a maximum which may be many hours greater than theminimur'n.

. While I have illustrated and -described witl'i particularity only. single .'preferred form 20f my invention, I donot desireto be limited to the exact details thus illustrated anddescribed, but intend. to cover'all forms and arrangements that comev withinthe definitions'of my invention constituting the appended claims.

vI claim:

l. Acircuit controhercorr singia'rotat'able cam having a camface that increases progres ivelyin its radial'distancefromlthe of .rottw tion..from. alowpoint. to. a highifpoint, lever extending past said; cam. and. hi'ngediationejend for.swinginggmovernents aboutanaxi and has ing at its othenend afingerpiece .parailellto said and a switchrneans mountedon said. lever so as. to be movable. bodily towardgandiaway iromthecarn as the lever swung toward .frornthe campsaid switch means having .a rockble arm arranged tangentially .of and .,engag.ed withthe..cam,.,and a spring interposed between saidarrn and, said lever and pressing the arm yieldin lyagainst the cam,

2..A circuit. controller comprising anrotatable camin the formof a disc the edgeof which 8 one turn of. ajspiraLa lever, extending past, said carnandhinged atone endfor swin in movements aboutan axis parallel tothe axis of,.rotation of the cam, means frictionallyholdil g the lever in its various angular positions, and a switch means mounted on said lever so .as tobe movable bodily toward and awayjfrom the cam asthe lever is swung toward and 5mm the. cam; said,switch means having a, ro ckable arm ar a e tangentially fa d eneaee w th theeds of the cam and a spring interposed between said arm and said lever and pressing the arm yieldingly against the cam.

ir it. c n oll com rising ppwsr driven rotary cam in the form of a disc the edge that comprises a section of a spiral, with an abrupt drop from the high point to the low point, a lever extending past the disc and hinged at one end for limited swinging movements about an axis parallel to the axis of rotation of the disc, a switch means on the lever provided with a rockable, spring-held switch operating arm tangential to and bearing against the edge of the cam in all positions of the lever, the arm being in a switch-closing position while engaged with the low point on the cam, regardless of the position of the lever; the radius of the cam increasing from the smallest value at such a rate that the arm, while the lever is in one extreme position, assumes a switch-opening position whenever the point of contact between the arm and the cam has moved far along toward but is still at a substantial distance from the high point of the cam, and the latter distance decreasing progressively as the lever is shifted toward its other extreme position.

4. A circuit controller comprising a power driven rotary cam in the form of a disc the edge of which is one turn of a spiral, with an abrupt drop from the high point to the low point, a lever extending past the disc and hinged at one end for limited swinging movements about an axis parallel to the axis of rotation of the disc, a switch means on the lever provided with a rockable, spring-held switch operating arm tangential to and bearing against the edge of the cam in all positions of the lever, the arm being in a switch-closing position while engaged with the low point on the cam, regardless of the position of the lever; the radius of the cam increasing from the smallest value at such a rate that the arm, while the switch means is closest to the cam, assumes a switch-opening position whenever the point of contact between the arm and the cam has moved far along toward but is still at a substantial distance from the high point of the cam, and the latter distance decreasing progressively as the lever is shifted toward its other extreme position.

5. A circuit controller comprising a lever pivoted to swing about a stationary axis, a switch on said lever tending constantly to remain open, said switch including a spring blade, anchored at one end and having the other end free, that must be flexed to close the switch, an actuator mounted on the lever beside the switch for rocking movements about an axis parallel to the aforesaid axis, a shoe of insulating material mounted on the actuator for rocking movements thereon about the same axis as the actuator, stops on the actuator to limit the rocking movements thereon, the shoe having an arc-shaped edge engaging said blade near the free end of the latter to close the switch, a spiral cam mounted to revolve about a stationary axis parallel to the aforesaid axes in the plane of the actuator and having a part engaging and tangential to the cam, and a spring holding the actuator against the cam and the shoe against said blade to flex the latter into switch-closing position; the said arc-shaped edge of the shoe being of such length that it engages the blade whenever the actuator contacts the low portion of the cam and the shoe is at one of said stops whereas, when the shoe is at the other of said stops and the actuator engages an intermediate point of the cam, depending on the angular position of the lever, said edge of the shoe is in position to pass beyond the free end of the blade and allow the switch to open.

6. A circuit controller comprising a lever pivoted to swing about a stationary axis, a switch on said lever tending constantly to remain open, said switch including a spring blade, anchored at one end and having the other end free, that must be flexed to close the switch, an actuator mounted on the lever beside the switch for rocking movements about an axis parallel to the aforesaid axis, a shoe of insulating material mounted on the actuator for rocking movements thereon about the same axis as the actuator, stops on the actuator to limit the rocking movements thereon, the shoe having an arc-shaped edge engaging said blade near the free end of the latter to close the switch, a cam, in the form of a disc the edge of which is one turn of a spiral with an abrupt drop from the high point to the low point, mounted to revolve about a stationary axis parallel to the aforesaid axes in the plane of the actuator and having a part engaging and tangential to the cam, a spring holding the actuator against the cam and the shoe against said blade to flex the latter into switch-closing position; the said arc-shaped edge of the shoe being of such length that it engages the blade whenever the actuator contacts the low portion of the cam and the shoe is at one of said stops I whereas, when the shoe is at the other of said stops and the actuator engages an intermediate point of the cam, depending on the angular position of the lever, one end of said edge of the shoe is in position to pass beyond the free end of the blade and allow the switch to open; and the said blade having a wedge-shaped projection, on the outer side at the free end, to engage the shoe and cause the blade to be lifted into switchclosing position on the shoe whenever the actuator drops from the high point on the cam to the low point.

7. A circuit controller comprising a rotatable cam having a cam face that increases progressively in its radial distance from the axis of rotation from a low point to a high point, a lever extending past said cam and hinged at one end for swinging movements about an axis parallel to the aforesaid axis, a switch mounted on said lever so as to be movable bodily toward and away from the cam as the lever is shifted, said switch including a blade that tends constantly to assume a predetermined position, a rockable shoe on the lever beside the blade and shaped to engage the blade and hold it out of or allow it to remain in said predetermined position depending on the angular position of the shoe, a rockable arm on the lever arranged tangentially of and engaged with the cam, said arm having thereon elements to engage and shift the shoe, and a spring on the lever pressing the arm yieldingly against the cam.

8. A circuit controller comprising a rotatable cam having a cam face that increases progressively in its radial distance from the axis of rotation from a low point to a high point, a lever extending past said cam and hinged at one end for swinging movements about an axis parallel to the aforesaid axis, a switch mounted on said lever so as to be movable bodily toward and away from the cam as the lever is shifted, said switch including a blade that tends constantly to assume a predetermined position, a rockable shoe on the lever beside said blade and shaped to engage said blade and allow it to remain in or restrain it from moving into said predetermined position, depending on the angular position of the shoe, a rockable arm on the lever arranged to mqve tlief s'hoe'end cpritrbI-its position, and a spring on the ever blessing the arm yieldingly {g b ireuit id'rit'reller 'alsset forth in claim 8, whei'ein the 8130155 611 the arm are 'Spa'ded apart shp'e thetffeetfa'i rjsthe switch bladehas a point of abrupt t'eimihatibn, and the blade is provided 'with a "weiiiffig elen'fenft to drive 'tHeSHdeahEald when mat "elmfit ah'd s'li'd point doincide.

DAVID MORRISONV "REFERENCES CITED Thefeillowin'g references are of record in the file of this patent:

UNITED STATES PATENTS 

